Don't do it. The race to the bottom helped put the PC industry in the sad state it is today. I hope they don't start sacrificing standards for the sake of short term sales.
The PC industry is doing just fine lmao. A low cost affordable Macbook ain't gonna ruin the Mac like you think it will since it's just one product out of many others. Did the Mac Mini ruin the Mac when it was introduced? No. It made so many people switch to Mac since there was now a desktop Mac they could afford. (It got me to switch after all)
A low cost Macbook will only bolster the lineup and add even more value to the more expensive Macs, just like the iPhone SE and Apple Watch SE did.